1. Field of the Invention
The invention relates to a seam construction for joining the ends of a belt, thereby making it endless, and more particularly relates to a pin seam construction for making endless a flat woven, multi-layered papermakers wet felt, dryer felt or forming fabric.
2. Brief Description of the Prior Art
The art is replete with descriptions of pin seam constructions for paper makers felts; see for example the disclosures of U.S. Pat. Nos. 3,436,041; 3,653,097; 4,026,331; and 4,006,760. In general, the seam constructions of the prior art have not been entirely satisfactory for all purposes and applications. This is particularly true of seam constructions for press fabrics or wet felts, dryer felts or forming fabrics of multi-layered construction fabricated from polymeric, non-metallic yarns.
The pin seam construction of our invention is advantageous for making endless, flat woven papermakers felts or multi-layered weave construction. The seams are exceptionally stronger than prior art seams for the same applications, do not adversely affect the desired flat surface of the endless felt, (that is, the seam is of a profile mating with the profile of the fabric) and facilitate change and installation of felts on the papermakers machine. The seam construction of the invention also exhibits longer life than prior art constructions and eliminates the need for cover pieces over the seam to prevent marking of the carried paper.
It will be appreciated that there are a wide variety of forms of endless woven belts employed in the papermaking industry and referred to as papermakers felts. The term "papermakers felts" includes the form commonly referred to as a "screen" fabricated by weaving synthetic monofilaments or twisted multi-filaments together in an open weave. Although not subjected to any form of milling, and therefore not "felts" in the original sense of the term, these screen fabrics have become known as "dryer felts", "press felts" and "forming fabrics".